Draft control



`lune 19, -1934. BUTLER 111,963,0713' DRAFT CONTROL Fi'ledvMarch 14",195.3- 4 sheets-sheet -1 gmc/who@ W. L. BUTLER DRAFT CONTROL June 19',1934.

4 Sheets-Sheet Filed Marchl 14', 1933 ma y June 19 1934 w. l.. BUTLER y1,963,073

DRAFT CONTROL Filed March 1.4, 1953 4 Sheets-Sheet 3 Vn i2 `rrr l y I Il l@ l I A Jun# 19, 1934.

W. L. BUTLER DRAFT CONTROL Filed March 14, 1933 4 Sheets-Sheet 4 gmc/Mo@Gum/WM5 Patented June 19, 1934 UNITED STATES PATENT OFFICE My inventionrelates to draft control devices, and means for controlling the same andhas for its object to provide a self acting draft control set in theiiue pipe and actuated primarily by the ue draft, but also actuated byback draft and lack of draft.

A further object is to provide a draft control device having a pivotedcontrol plate mounted at the juncture of the walls of three chambers,one

of which chambers is in connection` with the flue pipe from the furnace,one of which is in connection with the -flue leading to the stack andthe last, open to the atmosphere surrounding the furnace.

A still further object is to provide a draft controlled plate of suchweight as to be lifted only by draft, greater than that desired forcomplete combustion in the fire box of the furnace.

A still further object is to provide a control in connection with thedraft controls which will throw the current switch, wall motor, electricshut off valves, draft controls and blowers connected with the furnaceso that there will be no re should the flue become clogged, or completelack of draft exist for a predetermined period of time.

A still further object is to provide an adjustable damper for adjustingthe size of the orifice leading from the furnace side of the device intothe flue chamber-side.

A still further object is to provide a safety device for use on furnacesto protect the flame of the burner, or the pilot light and prevent anydanger of production of carbon monoxide gas.

These and other objects I accomplish with the devices shown in theaccompanying drawings in which similar numerals and letters of referenceindicate like parts throughout the several views and as described in thespecification forming a part of this application and pointed out in theappended claims.

In the drawings in which I have shown the best and mostpreferred mannerof building my invention,

Figure 1 is a vertical section through the horizontal type of draftcontrol showing arrows to indicate the direct ue draft and dotted linesand arrows to show the operation of the control plate and direction ofair currents.

Figure 2 is a side elevation of the partition casting in which the portsof the control are formed.

Figure 3 is a plan View of Figure 2.

Figure 4 is anend view of the partition dividing the space above thecontrol into two chambers.

Figure 5 is a vertical section of the vertical type of control. l

Figure 6 is a plan view of Figure 5.

Figure 7 is an inverted plan view of Figure 5.

Figure 8 is a plan view of the draft control 60 plate.

Figure 9 is a vertical section of a horizontal type of draft control,showing a modiedform of making the pivoted control portion of thedevice.

Figure 10 is a side elevation of one of the control plates showing themounting bearing on the opposite side and one method of balancing theplate.

Figure 11 is a plan `view of one of the control 70 plates showinganother form of counter balance and showing one of the support bearingsmounted outside the outer casing of the entire device, parts sectioned,and other parts cut away.

Figure 12 is an end View of Figure 9. y

Figure 13 is an end view of one of the devices showing the throw outcontrol.

'Figure 14 is a face view of the control used to shut down the lreshould the flue become clogged.

Figure 15 is a side elevation of the device 80 shown as though mountedon the shaft carrying the control plate.-

Figure 16 is a side elevation of a common pipe with a floating platemounted therein to shut down the re should the iiue become clogged.

Figure 17 is a plan View of a double' contact type of mercury tube.

Figure 18 is a diagrammatic view of a furnace and flue with my deviceused therein.

In the drawings I have shown the device as made of a rectangular casingA, mounted in the furnace fiue E by removing a section of pipe andsecuring the fiue pipe E1 of the furnace 'F to the inlet pipe 1 of thecasing A and outlet pipe 2 of the casing to the flue E.

The interior of the casing A is divided into three chambers the chamberB being termed the furnace chamber, the chamber C being termed the iiuechamber, and the chamber C termed the atmospheric chamber of the casing.The parti- 100 tion 3 divides the lower portion of the casing to formthe furnace chamber B, and the partition 4`divides the upper portion ofthe casing above the partition 3 into the two chambers C and D. Thepartition 3 is formed with two faces 6 and 7, 105 each sloping outwardlyand downwardly from a medial horizontal portion 8, at an angle thereto.The face 6 is secured to the end of the casing A and the face 7 isturned down at 7a to the bottom of the casing A. Ports. 10 and 11 areformed 110 through the faces 6 and 7 respectively of the partition and aclosure valve 9 is pivotally supported by pivots 12 on the top side ofthe portion 8 of the partition 3, so spaced from the horizontal portionthat the valve will close either of said ports, depending upon thedirection of draft through the casing A, or lack of draft therethrough.'Ihe valve will close one port at the'same time opening the other port.f s

An adjustable damper plate 5 is secured to the portion 7a of thepartition 3 by bolts 5a and the damper is provided with a slot thereinto allow for adjustment..

A draft relief port 14 is provided through the partition 4 and is closednormally by a plate valve 15 resting thereover. `'Ihe plate valve isprovided with two spaced apart slots 16 ladjacent, the

ends thereof through which positioning rods 1'7 are passed. The rods 1'7are secured through the partition 4 and are merely to hold the valveplate 15 in position over the port but at no time hindering ordampening, the action of the valve. This valve is mounted in this mannerto allow excess draft to act upon the valve andA open it to relieve theexcess suction from theflue preventing secured in the casing A.

The control valve 9, may be so mounted as to normally hold the port 11closed and still be draft responsive.

In Figures 10 and 11 different types of counter balances are shown. Thetype shown in Figure 10 being made by inserting a bolt 20 through thevalve 9, bending the bolt down to parallel with the valve and thenscrewing a weighted nutr 21- up or down the lower end of the bolt. InFigure 11 I pass an eye bolt 22 through the valve 9 and then through thethreaded eye thereof, I screw a bolt 23 with the head of the bolt theadjusting weight and the bolt may be screwed tperfect adjustment of thevalve 9. Other forms of bal,- ancing the valve may be used, such asgrinding off one end thereof or adding solder or other weight to the endas necessary. In Figure 5 I have shown the vertical type of device inwhich the casing A is divided into three chambers. In this device theplate valve 15 is mounted on the bottom end 27 of the casing A with theport 26 through the end 27. The partition 4 has no opening therein butmerely divides the chamber above or to one side of the partition 3. Inthis figure I have also shown the mounting of the valve 9 as formed ofextended shafts 28 on each side thereof with the shafts set in rollerbearings 29, which roller bearings may be secured to the inner wall ofthe casing A or if desired the shafts 28 may be extended through thewall of the casing A and the bearing mounted in suitable bracket 30 onthe outside of the casing.

In Figure 9 I have shown the same` type of casing, partitions', andports, as that shown in Figure l, but have formed the closure valves asmade of valve plates 31 and 32 mounted from a bar 33, which bar 33 ispivotally secured in the medial portion or shaft 34 carried by bearings35.

In Figures 13 and 15, I have shown av method of automatically turningthe re on or off in the furnace by attaching a specially shaped mercurytube to the end of the pivot shaft of the valve 9. The mercury tube 40is formed of a glass tube 41 having each end closed and having themedial portion drawn in to form a small orice 42, with fixed contactposts 43 and 44 carried through one end, said contacts to be used tocomplete an electrical circuit when the mercury has al1 passed into thatend of the tube to complete the contact between the posts 43 and 44 tocomplete the electrical circuit. The tube is supported by brackets 46and 47 formed on a support 48 and the support is carried in acylindrical protection frame 49 with a glass cover 50 thereover. Wires51 and 52 lead from the contacts 43 and 44 to an electric shut off valve54 or to a wall motor or other similar device. The motor or valve shutsoff the flow of fuel into the furnace.

This device is so constructed as to provide means for shutting off there when the flue becomes clogged. Theparticular shape of the mercurytube allows for normal movement of the valve 9 without actuating thetube enough to flow suilcient mercury through the orifice to makethe'contact, but should the flue become clogged, the lack of draft willclose the valve 9 and when held in this position a predetermined periodof time, the mercury will flow through the orifice and the contactbetween the points 43 and 44 will be made thereby shutting off thecurrent.

In Figure 16, I have shown the use of this device as operated on afloating vane in any flue so that should the flue become clogged thedraft therethrough will.cease and the mercury tube will be actuated,shutting off the re, by the contact formed.

In Figure 14 I have shown the outer casing as carrying a lug 56 on oneside thereof, said lug to be actuated by a lever arm 57 carried on theend of the pivot lever of the valve 9 providingv different means foractuating the mercury tube. It is also possible to mount the tubedirectly on ,the end of the shaft eliminating the casing, but thepreferred methods are herein shown.

In Figure 17 I have shown a type of mercury tube in which doublecontacts 58, 59, 60 and 61 are carried in the mercury tube, one pairineach end, so that the throw of the tube will complete a circuit at thesame time breaking another cir-` cuit. This type must be used where wallmotors are used to shut olf the fuel to the furnace.

This device is used to prevent carbon monoxide gas poisoning and toprevent-excessive moisture from collecting in the furnace room at thesame time it will act as an indicator to tlie furnace operator thatthere is something wrong with his flue.

, The operation of my invention is as follows:

Under normal conditions when the flre is ofl` the valve 9 remains in theclosed position with the valve 9 closing the port 1l. This is to preventdrawing of cold air through the furnacey if off or just the pilot lightburning. When the furnace is turned on the gases actuate the valve,opening the port 11, at which time the draft from the flue willcompletely open the valve, closing off the port 10. Should a neutralcondition occur the valve 9 will again close theport 11, opening theport 10, allowing the gases to enter the atmosphere through the open endof the casing A. The opening of the port 10 opens an area equal to orgreater than the area of the inlet pipe 1. f

Normal draft conditions will open the valve 9 from the port 11 and holdit in the open position.

Excessive draft will hold the. valve 9 open from the port 11 at the sametime raising the plate 15 from the port 14 commensurately with theamount of excess draft condition. This is to relieve excessive draftthrough the port 11 and in the combustion chamber of the furnace.

As the draft varies the position of the valve plate 15 varies therewithand should the draft drop the valve 15 closes. Should a back draftoccur, the valve 15 will be seated and the valve 9 will instantly closethe port 11, opening the port 10 and allowing the gases to escape intothe atmosphere, without the back draft affecting the fire or combustionconditions in the combustion chamber of the furnace re box.

When a low draft condition occurs, /the valve l5 is in closedpositiongiving full benefit of all the draft through the flue.

Having thus described my invention I desire to secure by Letters Patentand claim:

1. In a draft control device the combination of a casing; partitions insaid casing dividing it into three chambers; a poriI leading from onechamber to the atmosphere; an inlet pipe into one chamber and an outletpipe into the last chamber; a pivoted control valve mounted in the spacebetween the partitions adapted to close or open a port through one ofsaid partitions at the same time opening or closing a port in the otherside of said partition to direct air currents through one of said portsor gases therefrom into the atmosphere through the atmospheric chamber,or to direct gases through the other of said ports and into the outletpipe tothe flue; and a draft responsive plate carried in said casing toopen when the suction from the fiue reaches a predetermined velocity.

2. In a device of the class described the combination of a casing;partitions dividing the casing into three separate chambers with one ofsaid chambers open to the atmosphere; a. valve mounted to controlia portfrom one of said chambers into the open chamber or into the otherchamber, depending upon suction or pressure in the last mentionedchamber; and pipes to connect the other two chambers with the furnaceand flue.

3. In a device of the class described the combination of a chamberdivided into three chambers one of which is in connection with thefurnace, one with the iiue, and one with the atmosphere; a valve mountedto control thefsuction from the furnace chamber into the flue chamber orto direct gases from the furnace chamber out through the atmosphericchamber; and a valve in the fiue chamber actuated by increased suctiontherein.

4. In a device of the class described the combination of a furnace; apipe leading therefrom; a draft control casing mounted onto said pipe; aflue pipe attached to said casing and to the draft flue; partitions insaid casing to divide the casing into three chambers, one open to theatmosphere surrounding the furnace, one open to the furnace pipe and thelast open to the flue draft pipe; a Valve to control ports through onepartition in said casing to direct gases from the furnace pipe intoeither the atmospheric chamber or the chamber leading into the fluedepending upon the draft, lack of draft, or back draft, in said flue;and a valve to be opened' by excess draft through the flue to hold thedraft in the furnace constant. WILLIAM L. BUTLER.

